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Under water

I know this is the sort of thread that has been asked time and time, but does any body have any good tricks, tips, tuts for doing undersea scenes, specifically for the under surface parts for getting all that twinkling light distortion you see through the surface when looking at the sun, godrays and so on, the physical shape is easy enough with deformers like hot, but its the transparency of the surface that is tripping me up,
maybe any other elements you would use to sell the scene as believable? Stobbs under sea animation was great, and there was a small glimpse of what I mean by the sun effects near the start of his animation but unfortunately he seems not to have been active for some time to provide any tricks (weather he would be allowed to or not for that matter)

those cut aways and sea materials looks great, I think I missed all that and checking those out while it was hot..will have to look in to that.

otherwise simple volumetric lights over a transparent surface that has a procedural in the tranpsparency channel might work for some underwater scenes, previously volumetric was quite slow to deal with, but with 2015 I think that changed a lot, except for it crashing a lot in my case, but that is another story.

water surface needs to be double sided for the volumetric light to take effect, I might be able to record a vpr sample of how fast and how it looks like based on the lightwave mantra scenefile, which I just modified.

I think this is the video... (not got 40 odd minutes to review right now), but if I remember correctly, the Finding Nemo making of has some interesting insights/observations about creating underwater scenes. Probably worth a watch in the background while you're doing stuff.

thanks, unfortunately that first tutorial has been missing for a while, and may not help as much as I need to be in the water, I have since been having a little more luck with light coming through the surface as I suddenly noticed that my lightwave keeps defaulting raytrace refraction to off (it would usually be on as default when you start layout) and I am guessing the way the light is broken up is a direct result of refraction, the other problem seems to be with materials them selves, they can look good on their own but some of them like sigma seem to ignore elements that are behind them,

The content library in Lightwave four includes a scene from the popular Sea-quest television show. (Image below)
Faked water density and faked volumetric lights. I was amazed back then, but it doesn't hold up today.
Anyway, it includes a few tips and tricks that is still relevant today.

I don't know if it will help with what you're trying to accomplish, but you might have some success using a displaced subpatched object with Fast Fresnel, a high glancing angle, and the Corona image filter. Attached is a sample scene. The water surface has a refraction index of 1.31 and is 99% transparent. I used Ripple2 and Turbulence to displace it, and didn't really try to fine-tune the water surface for realism.

I used high values on the Fast Fresnel's Luminosity influence and have the Luminosity of the water surface based upon an Incidence gradient, so the effect is really obvious. You may want something more subtle. Note that VPR does not do raytraced refraction or the Corona effect, so you have to do an F9 render to see the refraction and coronas.

I used SkyTracer2 as the backdrop to give some sky detail, but that causes an "error" when clearing the scene of "There must be at least one light in the scene". Don't know why.

rustythe1..do you really need a displaced water surface? seems to me it should be enough with single poly water surface, with transparency procedural on it, and I also wonder if it is really needed to have the full water as an object volume with all those materials instead of just using a water surface, then add a volumetric light ..you will get your godrays/light shafts, it will look decent I think when looking from beneath the water, the lightshafts will be able to hit underwater fishes and terrain if done right, so I am not sure why it needs to be more advanced than that?
unless you need to go from above water to beneath water and perhaps up again? then you would need displace, but you could still just use a subpatch surface and skip advanced materials and use volumetric lights instead.

Yes, whether you need an actual water surface or not depends on whether you'll be looking through it. If all you want is the underwater refractive / caustic artifacts of an unseen water surface, volumetric spotlights work great. Attached is a sample scene with a basic underwater setup. The Spotlight volumetric light has a Projection Image which is also a component of the volumetric light texture, as well as a Noise image to provide the "glory" streaks.

and with some stuff in the scene, in which I increased the Height of the Volumetric light to increase the effect:

You can use an image sequence or movie file instead of the still and the pattern on the ground (the Projection Image) and the volumetrics will move. You can use Procedural Textures in the Volumetric Light texture (e.g. Underwater), but the Spotlight Projection Image doesn't allow them. I've also attached a "texture generator" scene which will generate an image sequence for the Underwater texture to be applied.

I forgot to mention: the other components of the underwater setup I posted are a Particle Emitter with HV's to provide particulates, an underwater color gradient backdrop, and linear fog which uses the backdrop colors.

Yes, whether you need an actual water surface or not depends on whether you'll be looking through it. If all you want is the underwater refractive / caustic artifacts of an unseen water surface, volumetric spotlights work great. Attached is a sample scene with a basic underwater setup. The Spotlight volumetric light has a Projection Image which is also a component of the volumetric light texture, as well as a Noise image to provide the "glory" streaks.

and with some stuff in the scene, in which I increased the Height of the Volumetric light to increase the effect:

You can use an image sequence or movie file instead of the still and the pattern on the ground (the Projection Image) and the volumetrics will move. You can use Procedural Textures in the Volumetric Light texture (e.g. Underwater), but the Spotlight Projection Image doesn't allow them. I've also attached a "texture generator" scene which will generate an image sequence for the Underwater texture to be applied.

Good luck!
mTp

Yes..that works too, but the problem with a projection image is that you will ...as you say have to go for unseen water surface, I suggested to use a volumetric light, And with a procedural texture or causting generated image directly on the actual water surface... and on the transparency channel, so when you look up it will look pretty decent, as if it were a rippled water surface, I will record that tomorrow I think and put it on the tube.

ItWould be interesting to see what kind ofproīs and conīs there are between these two methods.

In the 11.03 content...there is a manta underwater scene, there is a volumetric light in there but not active and som fog ...I used that and changed a lot of settings, there is underwater particles there too in the form of partigons from points, though I would replace that with real particles and a mix of bubble hv surface mode and smaller pollution with hv sprites.

Oh..what the heck, I managed to put aside a few minutes right now, just a quick recording on how it may look, though I do not go in to detail about the surfacing or the settings of the volumetric light.
The light rays are hitting the manta correctly as it should.

The scene is the manta scene in the lightwave 11.03 content, but you wonīt find the volumetrics and surface setup in there, that I modified and added to the scene.

thanks for the replies everyone, yes that works quite well Prometheus, the chorona filter I had forgot about but that's more or less the missing element, its that little twinkle that helps to sell it a bit more, and no I cant use a flat plane as there is interaction with other elements and above and bellow elements